Step 1: Preheat the Oven: Preheat the oven to 375F (190C). Lightly grease a 9x13 inch baking dish. This ensures the casserole does not stick.
Step 2: Prepare the Chicken Mixture: In a large bowl, combine the leftover fried chicken, cream of chicken soup, milk, thawed mixed vegetables, and black pepper. Stir until well combined, ensuring all ingredients are evenly distributed.
Step 3: Assemble the Casserole: Pour the chicken mixture into the prepared baking dish. Arrange the biscuit quarters evenly over the chicken mixture. The biscuit pieces should cover most of the surface.
Step 4: Add Melted Butter and Cheese (Optional): Drizzle the melted butter over the biscuit quarters. If desired, sprinkle the shredded cheddar cheese over the biscuits. The butter adds flavor, and the cheese creates a golden-brown top.
Step 5: Bake the Casserole: Bake in the preheated oven for 20-25 minutes, or until the biscuits are golden brown and the chicken mixture is bubbly. Monitor the biscuits to prevent over-browning.
Step 6: Cool Slightly and Serve: Remove the casserole from the oven and let it cool for a few minutes before serving. This allows the casserole to set slightly and prevents burning.
Tips: Substitute cream of mushroom or cream of celery soup for cream of chicken. Add a dash of hot sauce for a spicy kick. Fresh herbs, such as parsley or thyme, enhance the flavor.